Method of vulcanizing caoutchouc and product produced thereby



Patented May 4, 1926.

UNITED STATES PATENT OFFICE.

LOBIN B. SEBBELL, OI AKRON, OHIO, ASSIGNOR TO THE GOODYEAR TIRE & RUBBER COMPANY, OI AKRON. OHIO, A CORPORATION OF OHIO.

METHOD VULGANIZI'N'G OAOUTOHOUC AND PRODUCT PRODUCED THEREBY.

Io Drawing. Original application filed February 9, 1924, Serial No. 891,854. Divided and this application Med December 28, 1925. Serial No. 77,411.

My invention relates to methods of vulcanizing rubber and rubber compounds, and it has, for its primary object, the provision of methods of vulcanization which shall insure products of high quality, especially adapted for the construction of various rubber articles, and in particular, pneumatic tire casings.

It is well-known, of course, that accelerators are very desirable in producing vulcanized rubber possessing suitable characteristics to adapt it for the manufacture of many rubber articles, of which pneumatic tire casings form an outstanding example...

The accelerators are employed, not only as catalysts, but also to obtain certain desired physical properties in vulcanized rubber compounds, which will enhance their value 1n many appllcatlons. For example, some accelerators are especially deslrable because they impart such physical characteristics to the vulcanized compound that it ages exceptionally well, which is a desirable quality when it is employed in a great many capacities, particularly in rubber tires. Other accelerators impart other outstanding characteristics, which it is especially desired to secure. It will be apparent, then, that although there are a number of accelerators now known to the art, nevertheless each has its desirable features, and may be especially selected with a view to producing a final product which is particularly adapted for a certain use. 7

The present invention is primarily concerned with the disclosure of a number of accelerators of such character as to insure a vulcanized rubber product that is susceptible of general application.

It has been found, from extensive experimentation, that thiodiazoles are desirable 0 accelerators for general application. The

accelerators may be broadly designated as compounds of pentacyclic formation, containing two carbon atoms, two nitrogen atoms and one sulfur atom, with a. mcrcapto group joined to one of the carbon atoms.

enerlc claims to this class of compounds are made in copending application No. 691,-

854, filed February 9, 1924, while the present case, which is a division thereof, is restricted in scope to certain species, as will appear from a perusal of the claims.

Certain of the compounds may be somewhat more specifically indicated by the following structural formula:

which is numbered in accordance with the more modern form of nomenclature. In the latter formula, .if R is a henyl group, the resulting compound is designated as 3-phenyl-5-mercapto-l-2 4-thiodiazole.

be embodied in a. vulcanizing process, the following ingredients may be admixed in the proportions .set forth. j

Parts.

Rubber; Zinc oxide 2.5 Sulfur .'L 3 3-phenyl-5-mercapto-1-2-4*thiodiazole .5

accelerator is employed, either of which will serve as an activator for the accelerator, and

consequently increase its power to hasten the vulcanizingprocess. Such actlvators are preferably mixed with the accelerator to form a physical combination therewith. Metallic salts may also be employ ed to advantage with the accelerator as activators therefor, such salts being mixed with the ac- V, celerator in-the same manner as the metalllc oxides. Examples of such metalhc salts are As 4 'an example of how the latter compound may lead acetate, lead stearate, zinc acetate, zinc stearate, zinc benzoate or lead or zinc salts of other organic acids.

Metallic salts of 3-phenyl-5-mercapto-1-2- 4-thiodiazole, such as zinc, lead, cadmium and mercury, also provide accelerators having considerable merit and a capacity for general application. However, the metallic salts do not appear to be as powerful as the non-metallic compound alone or physically combined with zinc oxide, litharge, or the metallic salts.

A derivative of the above-mentioned ac celerator is found in 3-para-tolyl-5'mercapto- 1-2-4-thiodiazole, having the structural formula indicated as follows:

6 fr c-sH.

..g/ I l The metallic salts of this latter accelerator may also be utilized toadvantage, and litharge, zinc oxide or the lead and zinc salts also serve as activators therefor.

Anotheraccelerator, coming under the general classificationabove mentioned is 2-5- thio dimercapto-1-3-4-thiodiazole, the

structural formula having I I CJh-N-N s I -snt,

and indicated in Berichte, Vol. 27, page 2511, as phenyl-dithio-diazolonthiol. A plurality of derivatives may be obtained fromthis latter compound, one of which is 2- meth l-2-hydro-3-phenyl-5-mercapto-1- 3 4 diazole, having the structural formula .and indicated in Berichte, Vol. 28, page 2641 (1895), as henyl-methyl-thio-diazolinsulfhydrate.

nother derivative of the foregoing compound is 2-phenyl,-2-hydro-3- phenyl-5-mercapto-1-3-4-thiodiazole, having the structural formula corn-11 d d -sn,

and indicated in Berichte, Vol. 28, page 2643 (1895), as diphenyl-thio-diazol-sulfhydrate. As in the foregoing examples, the latter com pounds may be utilized in the form of metallic salts of a bivalent metal, such as zinc,

lead, mercury or cadmium. The activators may'also be advantageously utilized therewith.

The foregoing specifically named compounds may all be employed to advantage in rubber mixes for general application, but

it has been found that the compound 3- phenyl-5-mercapto-1-2-4-thiodiazole is probably the most powerful and desirable of the entire group named. However, the other compounds possess desirable characteristics, and may be found particularly advantageous for specific application. Examples might readily be given of rubber mixes incorporating each of the accelerators, but it is not believed necessary to an understanding of the invention, nor would such examples add materially to the disclosure thereof. Usually the amount of accelerator employed is in a proportion similar to the example given.

he activators are also used in an amount corresponding to the quantity of zinc oxide set forth in the example.

Although I have specifically named a plurality of compounds, as representing a class of compounds contemplated by my invention, it is obvious that the claims should not be restricted thereby, inasmuch as other compounds coming within the general classificatlon may be suggested thereby, and consequently, no limitations should be imposed upon the appended claims other than necessitated by the prior art. 7

What I claim is:

1. A method of accelerating the vulcanization of caoutchouc that comprises vulcanizing the same in the presence of a compoun having the general formula:

2. A method of accelerating the vulcancompound having the general formula:

' mula:

3. A method of accelerating the vulcanization'of caoutchouc that comprises vulcanizing the same in the presence of a zinc salt of a compound having the general formula:

:L- ca vulcanizing agent, incorporating in the mix a salt of a compound having the general for- N-N nd \g/ adding an activator thereto and applying heat.

6. A method of vulcanizing caoutchouc that comprises admixing caoutchouc with a vulcanizing agent, incor crating in the mix a zinc salt ofa compoun having the general formula:

' NIN n -d ii-sn. v I \g/ 1ald-zling an activator thereto and applying eat.

that comprises admixing caoutchouc with a vulcanizing agfnt, incorporating in the mix a compound aving the general formula:

' R'N-N adding an activator 'andapplying heat thereto.- Y

8. A method of vulcanizing caoutchouc that comprises admixing caoutchouc with a vulcanizing agent, incorporating inthe mix a salt of a compound having the general formula: 1 m-iz-n' nii-sn,

adding thereto.

7. Aimethod of vulcanizing caoutchouc an. activator and applying heat 9. A method .of vulcanizing caoutchouc that comprises admixing caoutchouc with a vulcanizing agent, incorporating in the mix a compound having the general formula:

n-i: Len adding an activator and applying heat thereto.

10. A-method of vulcanizing .caoutchouc that comprises admixing caoutchouc with a vulcanizing agent, incorplorating in the mix a salt of a compound aving the general formula adding an activator andapplying heatthereto.

11. A method of vulcanizing caoutchouc that comprises admixing caoutchouc with a vulcanizing agent, incorporating in themix 2 methyl-2-hydro-3-phenyl-5-mercapto-1-3- 4-thiodiazole, adding an activator and applying heat thereto.

12. A method of vulcanizing caoutchouc that comprises admixing 'caoutchouc with a vulcanizing agent, incorporating in the mix a zinc salt of 2-methyl-2-hydro-3-phenyl-5- mercapto-L3-4-thiodiazole, adding an activator and applying heat thereto. Y

13. A vulcanized caoutchouc product formed by the reaction of caoutchouc, a-vul-. camzing nt, an activator, and a com- 4 pound having the general formula:

- I 14. A vulcanized caoutchouc product formed by the reaction of'caoutchouc, a vulcanizing agent, an activator, and a compound having the general formula:

' I N-N a-ii d-sn.

15. A vulcanized caoutchouc productformed by the reaction of caoutchouc, a vulcanizi'ng agent an activator, and Q-methyl-Sf I hydro-3-phen -5 mercapto 1 4 3 4 thiodiazole.

16. A vulcanized caoutchouc product formed by the reaction of caoutchouc, a vulcanizing agent, an activator, and a zinc salt 3-4-thiodiazole.

- In witness whereof,-

I have hereunto signed my name.

LORIN B. SEBRELL.

' of 2-methyl-2-hydro-3-phenyl-5 mercapto-1- 

